I have a story set in the real world, more or less in the present day (it's a few years in the future, but I don't think that it's enough to significantly affect the answer). In the story, I have a character traveling by a normal commercial airline from Chicago to London. What I want to know is:
Let's say that the plane took off at roughly 6:00 am Chicago time (Central Daylight Time). What would be a reasonable range of time during which I could describe the plane as being over "the middle of the Atlantic"? All I really need is a rough estimate, but for simplicity please assume that the watch the character is using is still on Chicago time (CDT). Please take into account any "reasonable" assumptions about delays, additional stops, etc. I don't need any magic "exact" answer, just a time that I could justify as being not unlikely.
I tried googling things like "flight time from chicago to london", but the answers all varied wildly, and a lot of them seemed to have been calculated simply by dividing the straight-line distance between Chicago and London and dividing by the speed of a plane, without taking into account real-life things like delays, additional stops (if any), etc. I also looked up schedules for planes bound for London from O'Hare International Airport in Chicago, but they only confused me, and don't really answer my specific question since they only say when the plane landed in London.
Thank you in advance!
Edit: Thank you all for your answers; you were very helpful (and fast!). Sorry for bothering you with such a trivial question =P